.app {
  min-height: 100vh;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.app-header {
  text-align: center;
  margin-bottom: 30px;
  color: white;
}

.app-header h1 {
  font-size: 2.5rem;
  margin-bottom: 8px;
  font-weight: 700;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.app-header p {
  font-size: 1.1rem;
  opacity: 0.9;
  font-weight: 300;
}

.audio-selector {
  margin-bottom: 20px;
}

.story-selector-button {
  margin-bottom: 20px;
}

.story-select-btn {
  width: 100%;
  padding: 16px;
  text-align: left;
  height: auto;
  min-height: 70px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  border-radius: 12px;
  transition: all 0.3s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.story-select-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

.story-select-btn div {
  width: 100%;
}

.story-select-btn div > div {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 4px;
  color: inherit;
}

.story-select-btn small {
  font-size: 13px;
  opacity: 0.8;
  font-weight: 400;
  line-height: 1.4;
}

.audio-selector h3 {
  margin-bottom: 16px;
  color: #333;
  font-size: 1.2rem;
}

.audio-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}

.audio-list .btn {
  padding: 16px;
  text-align: left;
  height: auto;
  min-height: 80px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  border-radius: 12px;
  transition: all 0.3s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.audio-list .btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

.audio-list .btn div {
  width: 100%;
}

.audio-list .btn div > div {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 4px;
  color: inherit;
}

.audio-list .btn small {
  font-size: 13px;
  opacity: 0.8;
  font-weight: 400;
  line-height: 1.4;
}

.card h3 {
  margin-bottom: 16px;
  color: #333;
  font-size: 1.2rem;
  font-weight: 600;
}

.lrc-empty {
  text-align: center;
  padding: 40px;
  color: #666;
  font-style: italic;
}

.usage-guide ul {
  list-style: none;
  padding: 0;
}

.usage-guide li {
  padding: 8px 0;
  border-bottom: 1px solid #f0f0f0;
  line-height: 1.6;
}

.usage-guide li:last-child {
  border-bottom: none;
}

.usage-guide strong {
  color: #667eea;
  font-weight: 600;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .container {
    padding: 15px;
  }
  
  .app-header h1 {
    font-size: 2rem;
  }
  
  .app-header p {
    font-size: 1rem;
  }
  
  .audio-list {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  
  .audio-list .btn {
    min-height: 70px;
    padding: 14px;
  }
  
  .audio-list .btn div > div {
    font-size: 15px;
  }
  
  .audio-list .btn small {
    font-size: 12px;
  }
  
  .card {
    padding: 20px;
  }
  
  .card h3 {
    font-size: 1.1rem;
  }
}

@media (max-width: 480px) {
  .app-header h1 {
    font-size: 1.8rem;
  }
  
  .card {
    padding: 16px;
  }
  
  .usage-guide li {
    font-size: 14px;
  }
}

/* 动画效果 */
.card {
  animation: fadeInUp 0.6s ease-out;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.app-header {
  animation: fadeIn 0.8s ease-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}